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  1. #1

    Default Question about determining Axle Ratio

    Hi,

    I'm looking into the towing specs on my truck per the users manual. With my truck type, there are two options listed under axle ratio (3.73, 4.10). Can anyone tell me how to find out what the axle ratio on my truck is?

    Thanks,
    Theresa

  2. #2

    Default

    what kind of truck is it? someone will help you here for sure dont worry...
    PETE
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  3. #3

    Default

    Thanks. It is a 2003 Silverado 1500HD v8 6.0l crew cab with 4 x 4.

    Theresa

  4. #4

    Default

    in the glovebox you will see a sticker with a series of number/letter combinations. These are RPO codes and you can look up online what they stand for then match that to the ones in your glovebox.
    Dan
    1999 GMC Sierra 2500 350 vortec
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    ...and every one of em has issues

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  5. #5

    Default

    Correct, if you're certain the gears are the same as installed at the factory, you can use the RPO codes to determine what was installed at the factory.

    Alternatively, you can jack up the rear end, rotate the tires through one revolution if you pick both tires up, or through two revolutions if you only lift one tire, and count the number of times the driveshaft rotates.
    '98 K1500 Suburban LS 5.7 L 4L60E NV246 ARB
    '92 Ford Explorer XLT 4x4 4.0 L A4LD BW13-54 Trac-loc rear
    "My toys were the greasy cogs and springs and pistons that lay around all over the place, and these, I can promise you, were far more fun to play with than most of the plastic rubbish children are given nowadays." Danny in Roald Dahl's Danny The Champion of the World

  6. #6

    Default

    I really do need to post that RPO list I have on here, it is 180 pages long though.

    Here is a link to a RPO decoder on the web courtesy of our friends with corvettes.

    http://s-series.org/rpo/

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  7. #7

    Default

    Go to the dealership,give him your VIN number,he can then give you the info. you are looking for.

  8. #8
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    dwill3015's Avatar
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    Default

    I wonder if we have any GM techs here that can do VIN decoding. Here is a link to a VIN decode I had done on my Silverado on a diesel truck site. It is very detailed.
    Darcy
    Washington State
    2006 Silverado 2500HD LT3 4X4 CC SB Duramax LBZ
    Tuff Country 6" lift, 35" Toyo M/T's on 20" Ultra Peacemaker wheels, Quadzilla Stealth2 programmer, Diamond Eye 5" cat-back exhaust, factory Special order color Yellow.

  9. #9
    Jr. Apprentice WhosDatGuy's Avatar
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    Default

    My rear end is not factory, the elderly gent that I bought the truck off forgot the ratio, how can I find out what gears I'm running.

    Cheers

  10. #10

    Default

    Quote Originally Posted by WhosDatGuy View Post
    My rear end is not factory, the elderly gent that I bought the truck off forgot the ratio, how can I find out what gears I'm running.

    Cheers
    Method 1 (If you need to change the diff fluid anyway): Open differential. Count the # of teeth on the ring gear and the # of teeth on the pinion gear. RG/PG=gear ratio

    Method 2: Jack up both rear wheels. Put transmission/transfer case in N. Rotate rear wheels through one revolution while counting the # of times the driveshaft rotates. DS rotations/tire rotations=gear ratio. Often times, I prefer to jack up only one rear wheel and count the DS rotations through 2 rotations of that one tire. 2*DSrotations/tirerotation=gear ratio. I often prefer this because, with an open diff (or anything that behaves like an open diff like the stock G80) there might be some question with both wheels in the air if both wheels rotated exactly together.
    '98 K1500 Suburban LS 5.7 L 4L60E NV246 ARB
    '92 Ford Explorer XLT 4x4 4.0 L A4LD BW13-54 Trac-loc rear
    "My toys were the greasy cogs and springs and pistons that lay around all over the place, and these, I can promise you, were far more fun to play with than most of the plastic rubbish children are given nowadays." Danny in Roald Dahl's Danny The Champion of the World

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